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IMF dependence of the azimuthal direction of earthward magnetotail fast flows
Author(s) -
Pitkänen T.,
Hamrin M.,
Norqvist P.,
Karlsson T.,
Nilsson H.
Publication year - 2013
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2013gl058136
Subject(s) - physics , azimuth , interplanetary magnetic field , plasma sheet , solar wind , geophysics , current sheet , field line , flow (mathematics) , plasma , magnetic field , computational physics , magnetosphere , mechanics , magnetohydrodynamics , astronomy , nuclear physics , quantum mechanics
Cluster magnetotail data together with ACE solar wind data from 2001 to 2009 are used to investigate the dependence of the azimuthal flow direction of earthward magnetotail fast flows on the interplanetary magnetic field (IMF). We find an indication that fast flows have favored azimuthal directions that have dependence on the IMF. Our results suggest that for positive IMF B y , the favored azimuthal direction of the fast flows is dawnward in the northern plasma sheet and duskward in the southern plasma sheet. For negative IMF B y , an opposite situation takes place, the favored azimuthal flow directions are then duskward and dawnward in the northern and southern plasma sheet, respectively. As a possible explanation for the results, it is suggested that the untwisting reconnected magnetic field lines may direct the fast flows in the magnetotail, the field line twist itself being dependent on the IMF.